36 CHARLES F. W. MC CLURE, 



philous granules, the reader is referred to Fig. 14, which represents 

 a nerve cell of Helix fixed in sublimate and stained with iron-aluna- 

 haematoxylin. 



In this cell the same difference is observed, in the manner in 

 which the cell body and axis-cylinder process are stained. It is 

 clearly seen that this difference is due to the presence in the former, 

 of small, granular bodies which are deeply stained by the dye. 



This figure thus corroborates the fact that the granular structures, 

 which in sublimate-methylen blue-eosin preparations were stained blue, 

 here, likewise, stain in a distinctive manner which differs from that 

 of any other structures in the cell body or axis-cylinder processes 

 (spindles excepted). 



The above results, concerning the presence of chromophilous 

 granules in the nerve cells of Gastropods, point toward the acceptance 

 of the view that this chromophilous substance is homologous with 

 that found in the nerve cells of Vertebrates ^). 



The Spindles. (See Figs. 10, 11, 12, 13 and 14.) 



The progressive iron-haematoxylin method of staining cells, which 

 have been fixed in Flemming's solution, is the only method by means 

 of which I have been able to bring out these spindles with great 

 distinctness. 



In such sections they are clearly defined. By progressively dif- 

 ferentiating these sections, it is found that the spindles retain the 

 stain much longer than the more isolated granules. By continuing 

 the diflerentiation process, however, they give up their stain, and then 

 appear as localized collections of small chromophilous granules. 



These spindles are confined exclusively to the cell body, in which 

 they appear to be diffusely distributed. In some cells, however, they 

 appear to be more abundant in the endo- than in the ecto-plasmatic 

 layers of the cell. The direction of their long axes is usually (longi- 

 tudinal sections) parallel to the periphery of the cell, although in 

 regard to this point, no definite generalization can be made. 



In size, the spindles are, on the average, much smaller than the 

 chromatin granules of the nucleus, and larger than any individual 

 chromophilous granules in the cell body. 



1) In addition to Grastropods, this generalization applies equally 

 •well to the nerve cells of all Vermes and Crustacea thus far axamined 

 by me. 



